U.S. patent number 10,041,554 [Application Number 15/315,040] was granted by the patent office on 2018-08-07 for pad assembly for disc brake.
This patent grant is currently assigned to AKEBONO BRAKE INDUSTRY CO., LTD.. The grantee listed for this patent is AKEBONO BRAKE INDUSTRY CO., LTD.. Invention is credited to Kohei Bando, Hiroyasu Ishikawa, Akiyuki Tajima.
United States Patent |
10,041,554 |
Ishikawa , et al. |
August 7, 2018 |
Pad assembly for disc brake
Abstract
An engaging projection formed on a back surface of a pressure
plate is inserted into an engaging hole formed in an outside shim
plate. A flat surface parts of the engaging projection constituting
a side surface thereof are opposed to a linear parts of the
engaging hole constituting an inner peripheral edge thereof. When
the outside shim plate exists at a neutral position with respect to
the pressure plate, the flat surface parts and linear parts are
slightly inclined with respect to each other. A rotation of the
outside shim plate about an axis of a piston based on a rotation
force applied from a leading end face of the piston to the outside
shim plate is regulated by line contact between the flat surface
parts and linear parts.
Inventors: |
Ishikawa; Hiroyasu (Tokyo,
JP), Tajima; Akiyuki (Tokyo, JP), Bando;
Kohei (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
AKEBONO BRAKE INDUSTRY CO., LTD. |
Chuo-ku, Tokyo |
N/A |
JP |
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|
Assignee: |
AKEBONO BRAKE INDUSTRY CO.,
LTD. (Tokyo, JP)
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Family
ID: |
54833585 |
Appl.
No.: |
15/315,040 |
Filed: |
June 9, 2015 |
PCT
Filed: |
June 09, 2015 |
PCT No.: |
PCT/JP2015/066643 |
371(c)(1),(2),(4) Date: |
November 30, 2016 |
PCT
Pub. No.: |
WO2015/190495 |
PCT
Pub. Date: |
December 17, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170191540 A1 |
Jul 6, 2017 |
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Foreign Application Priority Data
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|
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Jun 9, 2014 [JP] |
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2014-118648 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16D
65/0971 (20130101); F16D 65/095 (20130101); F16D
65/38 (20130101); F16D 65/40 (20130101); F16D
65/092 (20130101) |
Current International
Class: |
F16D
65/40 (20060101); F16D 65/38 (20060101); F16D
65/092 (20060101) |
Field of
Search: |
;188/73.31,73.37,73.38,250R,251A ;D12/180 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1749592 |
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Mar 2006 |
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CN |
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H03-118328 |
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Dec 1991 |
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JP |
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A-H07-293608 |
|
Nov 1995 |
|
JP |
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2005-315422 |
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Nov 2005 |
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JP |
|
2006-200560 |
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Aug 2006 |
|
JP |
|
2007-315541 |
|
Dec 2007 |
|
JP |
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WO-2013/039174 |
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Mar 2013 |
|
WO |
|
Other References
Machine Translation in English for JP 3-118328 U; 3 pages; Retrieve
Date: Oct. 2, 2017. cited by examiner .
Extended European Search Report dated Jan. 16, 2018 in
corresponding European patent application 15806897.3 (5 pages).
cited by applicant .
Chinese Office Action, along with its English-language translation,
dated May 17, 2018 that issued Chinese patent application No.
201580031157.3 attached. cited by applicant.
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Primary Examiner: Williams; Thomas J
Assistant Examiner: Sy; Mariano
Attorney, Agent or Firm: Drinker Biddle & Reath LLP
Claims
The invention claimed is:
1. A pad assembly for a disc brake, the pad assembly comprising: a
pad in which a lining is fixedly attached to a front surface of a
pressure plate, and which is to be arranged to face an
axial-direction side surface of a rotor; and a shim plate having a
back surface to be pressed by a leading end face of a piston,
wherein the shim plate includes a'flat plate-shaped main body and a
locking piece folded from a peripheral edge of the main body toward
the pressure plate, wherein the locking piece is engaged with a
peripheral edge of the pressure plate in a state where a front
surface of the main body is superimposed directly or through
another shim plate on a back surface of the pressure plate, wherein
the pressure plate includes, in a part of the back surface of the
pressure plate which is shifted from a part of the pressure plate
opposed to the leading end face of the piston, an engaging
projection projecting in an axial direction of the rotor, wherein
the engaging projection is inserted into an engaging hole formed in
a part of the main body of the shim plate which is shifted from a
part of the main body to be contacted with the leading end face of
the piston in a state where a flat surface part of the engaging
projection constituting a side surface of the engaging projection
and a linear part of the engaging hole constituting an inner
peripheral edge of the engaging hole are opposed to each other and
where the flat surface part and the linear part are inclined to
each other with the shim plate existing at a neutral position with
respect to the pressure plate, wherein, of shifting movements of
the shim plate relative to the pressure plate, a movement of the
shim plate in a circumferential direction of the rotor is regulated
by an engagement between the locking piece and the inner peripheral
edge of the pressure plate, wherein, of a rotation of the shim
plate about an axis of the piston, a rotation in a direction to act
on the piston at least in braking is regulated, by a line contact
between the flat surface part and the linear part, and wherein, in
a state where the shim plate exists at the neutral position with
respect to the pressure plate, an inclination angle between the
flat surface part and the linear part is in the range of 0.degree.
to 15.degree..
2. The pad assembly for a disc brake according to claim 1, wherein
the engaging projections are formed on the back surface of the
pressure plate in both sides in the circumferential direction
across the part of the pressure plate opposed to the leading end
face of the piston, and wherein the engaging holes are formed on
the main body of the shim plate in both sides in the
circumferential direction across the part of the main body to be
contacted with the leading end face of the piston.
3. The pad assembly for a disc brake according to claim 1, wherein
a pair of flat surface parts are formed in the side surface of the
engaging projection, a pair of linear parts are formed in the inner
peripheral edge of the engaging hole, and the rotation of the shim
plate in both directions about the axis of the piston is regulated
by line contact between the flat surface parts and the linear
parts.
4. The pad assembly for a disc brake according to claim 1, wherein
the locking pieces are formed in outer and inner peripheral edges
of the main body at least apiece.
5. A pad assembly for a disc brake, the pad assembly comprising: a
pad in which a lining is fixedly attached to a front surface of a
pressure plate, and which is to be arranged to face an
axial-direction side surface of a rotor; a shim plate having a back
surface to be pressed by a leading end face of a piston, wherein
the shim plate includes a flat plate-shaped main body and a locking
piece folded from a peripheral edge of the main body toward the
pressure plate, wherein the locking piece is engaged with a
peripheral edge of the pressure plate in a state where a front
surface of the main body is superimposed directly or through
another shim plate on a back surface of the pressure plate, wherein
the pressure plate includes, in a part of the back surface of the
pressure plate which is shifted from a part of the pressure plate
opposed to the leading end face of the piston, an engaging
projection projecting in an axial direction of the rotor, wherein
the engaging projection is inserted into an engaging hole formed in
a part of the main body of the shim plate which is shifted from a
part of the main body to be contacted with the leading end face of
the piston in a state where a flat surface part of the engaging
projection constituting a side surface of the engaging projection
and a linear part of the engaging hole constituting an inner
peripheral edge of the engaging hole are opposed to each other and
where the flat surface part and the linear part are inclined to
each other with the shim plate existing at a neutral position with
respect to the pressure plate, wherein, of shifting movements of
the shim plate relative to the pressure plate, a movement of the
shim plate in a circumferential direction of the rotor is regulated
by an engagement between the locking piece and the inner peripheral
edge of the pressure plate, and wherein, of a rotation of the shim
plate about an axis of the piston, a rotation in a direction to act
on the piston at least in braking is regulated by a line contact
between the flat surface part and the linear part; and a folded
part folded at the inner peripheral edge of the engaging hole in a
opposite direction from the pressure plate, wherein an inside
surface of the folded part serves as the linear part.
Description
TECHNICAL FIELD
This invention relates to an improvement in a pad assembly for a
disc brake.
BACKGROUND ART
A disc brake to be used to brake a vehicle is structured such that
a pair of pads are arranged across a rotor rotatable together with
a wheel and, in braking, the two pads are pressed against the
axial-direction two side surfaces of the rotor. The basic structure
of such disc brake includes two kinds of structures, that is, a
floating type structure and an opposed piston type structure. Of
these two disc brakes, in the floating type disc brake, a caliper
with a piston built therein on the inner side is axially shiftably
supported on a support supporting the paired pads axially
shiftably. In braking, the piston presses the inner side pad
against the inner side surface of the rotor and, as a reaction of
this, the caliper is shifted toward the inner side. And, a caliper
pawl part formed in the outer side end of the caliper presses the
outer side pad against the outer side surface of the rotor. Also,
in the opposed piston type disc brake, multiple pistons are
disposed on a caliper with a pair of pads axially shiftably
supported thereon in such a manner that the pistons are arranged on
the axial-direction two sides of the rotor. In braking, the pistons
press the two pads against the axial-direction two side surfaces of
the rotor. In each type, the two pads are formed by attaching
linings to the front surface of a pressure plate having sufficient
rigidity. And, in braking, the back surface of the pressure plate
is pressed by the piston or the caliper pawl part, whereby the
front surfaces of the linings and the axial-direction two side
surfaces of the rotor are caused to rub each other.
Here, in this specification and Claims, terms [axial direction],
[circumferential direction] and [radial direction] respectively
mean the axial direction, circumferential direction and radial
direction of the rotor in a state where the disc brake pad assembly
is assembled to the disc brake, unless otherwise stated. Also, the
term [peripheral edge] means the inner peripheral edge or outer
peripheral edge of the rotor with respect to the radial direction
thereof.
In the disc brake of each structure, in braking, the rotor is
strongly held from the axial-direction two sides by the paired pads
and is braked by a friction force applied to the contact portion
between the linings constituting the two pads and the
axial-direction two side surfaces of the rotor. In such braking,
the portion to which such friction force is applied and the
portions where the piston or the caliper pawl part press the two
pads are shifted from each other along the axial direction by an
amount equivalent to the thickness of the two pads; and, due to
such shift, the attitudes of the two pads are easy to be unstable.
When the attitudes of the two pads are unstable in braking, the
behaviors of the two pads are hard to be smooth and thus they are
vibrated, whereby there are produced noises called "squeak" and the
uneven wear of the lining is easy to increase greatly.
In order to relieve such squeak and uneven wear, conventionally, it
has been widely known to hold a shim plate between the back surface
of a pressure plate constituting a pad and the leading end face of
a piston or the inside surface of a caliper pawl part which operate
as a pressure surface for pressing the back surface. Such shim
plate has a single plate structure constituted of a single plate
and, for enhancement in the relieving effect of the squeak and
uneven wear, there has been also widely employed a two-plate
structure in which an inside shim plate and an outside shim plate
are superimposed on each other. Also, whether a single plate
structure or a two-plate structure, locking pieces formed in the
multiple locations of the inside and outside two peripheral edges
of the shim plate are engaged with the inside and outside two
peripheral edges of the pressure plate, whereby the shim plate is
supported on the back surface side of the pressure plate.
The patent document 1 discloses, as a disc brake pad assembly, a
structure as shown in FIGS. 12.about.14. In this conventional
structure, a shim plate 5 constituted of an inside shim plate 3 and
an outside shim plate 4 is mounted on the back surface of a
pressure plate 2 constituting a pad 1. In the pad 1, a lining 6 is
fixedly attached to the front surface (the surface to be opposed to
the side surface of the rotor when the pad 1 is assembled to the
disc brake) of the pressure plate 2 by such a large connecting
force that can prevent it from being shifted due to a brake torque
applied thereto in braking. The inside shim plate 3 is made of a
metal plate such as a stainless steel plate and includes a flat
plate-shaped inside main body 7 and multiple inside locking pieces
8a, 8b, 8c. Also, the inside main body 7 includes multiple open
holes 9, 9 used to hold grease therein. Also, of the inside and
outside two peripheral edges of the pressure plate 2, the outer
pressure edge includes a locking recess 10 in the circumferential
direction central part thereof, while the inner peripheral edge
includes a pair of steps 11, 11 formed near to the circumferential
direction two ends thereof. While, of the inside locking pieces 8a,
8b, 8c of the inside shim plate 3, the inside locking piece 8a on
the outside diameter side is engaged with the locking recess 10 and
the inside locking pieces 8b, 8c on the inside diameter side are
engaged with the two steps 11, 11, the pressure plate 2 is
sandwiched from the radial-direction two sides thereof by the
inside locking pieces 8a, 8b, 8c. In this state, the inside shim
plate 3 is mounted on the back side of the pressure plate 2 in such
a manner that it is restricted (substantially, prevented) from
shifting in the peripheral and radial directions thereof.
Also, the outside shim plate 4 is made of a metal plate such as a
stainless steel plate and includes a flat plate-shaped outside main
body 12 and multiple outside locking pieces 13a, 13b, 13c. In this
outside shim plate 4, while the outside locking pieces 13a, 13b,
13c are superimposed on the inside locking pieces 8a, 8b, 8c
respectively, the outside main body 12 is superimposed on the
inside main body 7. In this state, the outside shim plate 4 is
assembled to the inside shim plate 3 in such a manner that it can
shift in the circumferential direction. Thus, the circumferential
direction width dimension of the outside locking piece 13a is set
smaller than those of the locking recess 10 and the inside locking
piece 8a, while the distance between the mutually opposed
circumferential direction outside edges of the outside locking
pieces 13b and 13c is set smaller than the distance between the two
steps 11 and 11.
Here, it has also been conventionally proposed to use the disc
brake pad assembly having the above structure while it is
incorporated into an electric disc brake such as a disc brake
equipped with an electric parking mechanism. In this electric disc
brake, there has been widely employed a structure in which a piston
fitted in a cylinder is pushed out toward a pad arranged on the
inner side by a conversion mechanism such as a feed screw mechanism
for converting the rotation motion of an electric motor to linear
motion. Also, to stop the rotation of the piston and receive a
rotation force transmitted to the piston by the conversion
mechanism, there has been used a technology that a recess is formed
in the leading end face of the piston and a dowel formed on the
back surface of the pressure plate of a pad arranged on the inner
side is engaged into the recess. Thus, when the disc brake pad
assembly having the above structure is used while it is
incorporated into the electric disc brake, a notch is formed in a
portion of a shim plate covering the back surface of the pressure
plate, whereby the dowel formed on the back surface of the pressure
plate is engaged into the recess formed in the leading end face of
the piston.
Meanwhile, when the above-mentioned dowel and recess rotation
preventive mechanism is employed, for reason of complicated control
of the electric motor or other, the inventors et al. have pushed
forward a study of a structure which omits the dowel and recess but
uses a friction force or the like acting on the piston to stop
rotation thereof. And, in this case, even when the disc brake pad
assembly is used, the rotation stop structure using the dowel and
recess is not provided but there is proposed a structure that the
leading end face of the piston is contacted with the back surface
of a shim plate constituting the disc brake pad assembly. However,
when this structure is employed simply, there is a possibility that
the following problems can occur.
That is, as shown in FIG. 14, in braking, a rotation force is
transmitted through the leading end face of a piston 14 to the back
surface of an outside shim plate 4 against which the leading end
face of a piston 14 is pressed. And, in a disc brake pad assembly
of a conventional structure, such rotation force is received by any
one of engaged portions between the outside locking pieces 13a,
13b, 13c provided on the peripheral edge of the outside shim plate
4 and the peripheral edge (locking recess 10 and steps 11, 11) of
the pressure plate 2. And, the outside shim plate 4 is restricted
from rotating relative to the pressure plate 2 about the axis O of
the piston 14. Thus, excessive stress is applied to the outside
locking pieces 13a, 13b, 13c, thereby raising a possibility that
they can be plastically deformed or can be damaged, for example,
can be broken through long use.
PRIOR ART DOCUMENT
Patent Document
Patent Document 1: JP-A-2006-200560
SUMMARY OF THE INVENTION
Problems that the Invention is to Solve
The invention, in view of the above circumstances, has an object to
provide a structure of a pad assembly for a disc brake which, even
when it is used while it is incorporated into an electric disc
brake, can effectively prevent locking pieces against deformation
and damage.
Means for Solving the Problems
The object of the invention can be attained by the following
structures.
(1) A disc brake pad assembly, comprising: a pad constituted of a
pressure plate with a lining fixedly attached to the front surface
thereof, and arranged opposed to the axial-direction side surface
of a rotor; and, a shim plate having a back surface to be pressed
by the leading end face of a piston, the shim plate including a
flat plate-shaped main body and a locking piece folded from the
peripheral edge of the main body toward the pressure plate, and the
locking piece being engaged with the peripheral edge of the
pressure plate in a state where the front surface of the main body
is superimposed directly or through the other shim plate on the
back surface of the pressure plate, wherein the pressure plate
includes, in such part of the back surface thereof as is shifted
from the part thereof opposed to (axially superimposed on) the
leading end face of the piston, an engaging projection projecting
in the axial direction of the rotor, the engaging projection is
inserted into an engaging hole formed in such part of the main body
of the shim plate as is shifted from the part thereof to be
contacted with the leading end face of the piston in a state where
the flat surface part of the engaging projection constituting the
side surface thereof and the linear part of the engaging hole
constituting the inner peripheral edge thereof are opposed to each
other, and the flat surface part and the linear part are inclined
to each other (here, when the other shim plate is held between the
pressure plate and shim plate, the leading end of the engaging
projection inserted through a through hole or a notch formed in the
other shim plate is inserted into an engaging hole formed in the
shim plate) with the shim plate existing at a neutral position with
respect to the pressure plate; of the shifting movement of the shim
plate relative to the pressure plate, the movement in the
circumferential direction of the rotor is regulated by the engaged
portion between the locking piece and the peripheral edge of the
pressure plate; and, of the rotation of the shim plate about the
axis of the piston, the rotation in a direction acting on the
piston at least in braking is regulated by line contact between the
flat surface part and the linear part.
(2) A disc brake pad assembly according to the above (1) structure,
wherein, in a state where the shim plate exists at a neutral
position with respect to the pressure plate, the inclination angle
between the flat surface part and linear part is in the range of
0.degree. (preferably, 0.5.degree.).about.15.degree..
(3) A disc brake pad assembly according to any one of the
structures (1) and (2), further including a folded part folded from
the inner peripheral edge of the engaging hole toward the opposite
side to the pressure plate, wherein the inside surface of the
folded part serves as the linear part.
(4) A disc brake pad assembly according to any one of the
structures (1).about.(3), wherein the engaging projection is formed
in such circumferential direction two side parts of the back
surface of the pressure plate as are disposed across the part
thereof opposed to the leading end face of the piston, and the
engaging hole is formed in such circumferential direction two side
parts of the main body of the shim plate as are disposed across the
part thereof to be contacted with the leading end face of the
piston.
(5) A disc brake pad assembly according to any one of the
structures (1).about.(4), wherein a pair of flat surface parts are
formed in the side surface of the engaging projection, a pair of
linear parts are formed in the inner peripheral edge of the
engaging hole, and the rotation of the shim plate in both
directions about the axis of the piston is regulated by line
contact between the flat surface parts and the linear parts.
(6) A disc brake pad assembly according to any one of the
structures (1).about.(5), wherein the locking pieces are formed in
the outer and inner peripheral edges of the main body at least
apiece.
Effects of the Invention
According to the above-structured disc brake pad assembly of the
invention, even when it is used while it is incorporated into an
electric disc brake, the locking piece can be effectively prevented
against deformation and damage.
That is, in a state where the engaging projection formed on the
back surface of the pressure plate is inserted into the engaging
hole formed in the main body of the shim plate, the flat surface
part constituting the side surface of the engaging projection and
the linear part constituting the inner peripheral edge of the
engaging hole are opposed to each other; and, in a state where the
shim plate exists at a neutral position with respect to the
pressure plate, the flat surface part and linear part are inclined
to each other. And, in braking, the rotation of the shim plate
about the axis of the piston based on a rotation force applied from
the leading end face of the piston constituting the electric disc
brake to the shim plate is regulated by line contact between the
flat surface part and linear part. Thus, in this invention, the
rotation force applied from the leading end face of the piston to
the shim plate may not be supported by the engaged portion between
the locking piece formed in the peripheral edge of this shim plate
and the peripheral edge of the pressure plate, or such supporting
force may be small. Therefore, according to the invention, the
locking piece can be effectively prevented against plastic
deformation or damage such as breakage.
Further, in this invention, the rotation force applied from the
leading end surface of the piston to the shim plate is supported
not by the portion to be point contacted but by the portion to be
line contacted between the flat surface part and linear part,
thereby enabling suppression of stress acting on the engaging
projection. This can effectively prevent the side surface of the
engaging projection and the inner peripheral edge of the engaging
hole against serious wear or deformation.
Also, according to the invention disclosed in the above (3)
structure, a large contact area can be secured between the flat
surface part and linear part, thereby enabling reduction in the
contact surface pressure acting on the two parts. This can further
effectively prevent the side surface of the engaging projection and
the inner peripheral edge of the engaging hole against serious wear
or deformation.
Further, according to the invention disclosed in the above (5)
structure, in braking removal time, the rotation of the shim plate
about the axis of the piston based on a rotation force applied from
the leading end face of the piston constituting the electric disc
brake to the shim plate can be regulated by bringing the flat
surface part and linear part into line contact with each other.
Thus, the locking piece can be prevented from being deformed or
damaged by the force acting on the shim plate in braking removal
time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an orthographic view of a pad assembly according to a
first embodiment of the invention, when viewed from behind.
FIG. 2 is an enlarged view of the A part of FIG. 1.
FIG. 3 is a perspective view of the pad assembly shown in FIG. 1,
when viewed from behind and radial-direction outside.
FIG. 4 is an exploded perspective view of the pad assembly shown in
FIG. 3.
FIG. 5 is a section view taken along the B-B arrows of FIG. 1.
FIG. 6 is a partial section view of a disc brake with an electric
parking mechanism, showing a state thereof where the pad assembly
of the first embodiment is incorporated therein.
FIG. 7 is a view similar to FIG. 1, showing a state where an
outside shim plate rotates counterclockwise when a parking brake is
in braking.
FIG. 8 is a view similar to FIG. 1, showing a state where the
outside shim plate rotates clockwise when the parking brake is in
braking removal time.
FIG. 9 is an enlarged view of a part corresponding to the A part of
FIG. 1 according to a second embodiment of the invention.
FIG. 10 is an enlarged view similar to FIG. 9 according to a third
embodiment of the invention.
FIG. 11 is a section view corresponding to FIG. 5.
FIG. 12 is a perspective view of an example of a conventional
structure, when a pad assembly is viewed from behind and
radial-direction outside.
FIG. 13 is an exploded perspective view of the pad assembly shown
in FIG. 12.
FIG. 14 is an orthographic view of the pad assembly shown in FIG.
12, when viewed from behind.
MODE FOR CARRYING OUT THE INVENTION
First Embodiment
FIGS. 1 to 8 show a first embodiment of the invention. A disc brake
pad assembly 15 of this embodiment is used while it is incorporated
into a disc brake 16 equipped with an electric parking mechanism,
and includes a pad (inner pad) 1a, an inside shim plate 3a
corresponding to the other shim plate stated in Claims, and an
outside shim plate 4a corresponding to a shim plate stated in
Claims. The pad 1a is formed by fixedly attaching a lining 6 to the
front surface of a pressure plate 2a and is arranged opposed to the
axial-direction side surface of a rotor 17.
The pressure plate 2a includes a locking recess 10a formed in the
circumferential direction center of the outer peripheral edge
thereof, a pair of steps 11a, 11a formed near to the
circumferential direction two ends of the inner peripheral edge
thereof, and an inside diameter side locking recess 18 formed in
the circumferential direction center of the inner peripheral edge
thereof. Also, in this embodiment, of the back surface of the
pressure plate 2a, in the circumferential direction two side
portions across a portion (oblique cross portion shown in FIG. 1)
of the back surface opposed to (superimposed on in the axial
direction) the leading end face of the piston 14a, there are
provided engaging projections (dowels) 19, 19 projecting in the
axial direction of the rotor 17 apiece. These two engaging
projections 19, 19 are formed more adjacently to the
radial-direction outside than the pad center position in a
direction parallel to the rotation direction (tangential direction)
of the rotor 17 in the circumferential direction center of the pad
1a. Also, the engaging projections 19, 19 each is formed in an oval
projection (long in the circumferential direction) having a section
shape (end face shape) in which a circumferential direction width
dimension L.sub.19 is larger than a radial-direction width
dimension H.sub.19. Therefore, the side surfaces (peripheral
surfaces) of the two engaging projections 19, 19 are structured
such that a pair of flat surface parts 20a, 20b arranged parallel
to each other in the radial-direction two side portions and a pair
of convex arc surface parts 21, 21 arranged in the circumferential
direction two side portions continue with each other. Also, the
projection amount of each of the engaging projections 19, 19 with
respect to the axial direction is set larger than a dimension
provided when the inside and outside shim plates 3a and 4a are
superimposed on each other. Also, the leading end faces of the two
engaging projections 19, 19 are formed as convex curved surfaces
the centers of which project most along the axial direction.
Also, the inside shim plate 3a is produced by punching and bending
by press working a corrosion resistant and elastic metal plate such
as a stainless spring steel plate or a stainless spring steel plate
with the surface thereof opposed to the back surface of the
pressure plate 2a coated with rubber. This inside shim plate 3a
includes a flat plate-shaped inside main body 7a, a pair of locking
folded parts 22, 22 folded substantially at right angles toward the
opposite side of the pressure plate 2a from the circumferential
direction two ends of the inside main body 7a, and three inside
locking pieces 8d, 8e and 8f.
In this embodiment, of the inside main body 7a, in the
circumferential direction two side parts existing across a part
opposed (matched) to the leading end face of the piston 14a, there
are formed through holes 23, 23 for insertion of the engaging
projections 19, 19. In the illustrated example, the through holes
23, 23 have an oval shape (a shape long in the circumferential
direction) identical with engaging holes 26, 26 (which is discussed
later). However, the shape and size thereof are not limitative so
long as they are capable of insertion of the engaging projections
19, 19. Also, in such portion of the inside main body 7a as
intervenes between the two through holes 23, 23 along the
circumferential direction, there are formed multiple (in the
illustrated example, 2) open holes 9, 9 (long in the radial
direction) for retaining therein grease for lubrication.
Also, in such width direction (radial direction) central portions
of the locking bent parts 22, 22 constituting the inside shim plate
3a as range from the base end portions to the middle portions,
there are formed locking open holes 24, 24, respectively. Also, in
such portions of the two locking bent parts 22, 22 as exist near to
the leading ends thereof, there are formed guide inclination parts
25, 25, respectively. The inclination direction of the two guide
inclination parts 25, 25 is defined as a direction where their
mutual distance increases as they go toward their respective
leading end edges.
Further, of the two inner and outer peripheral edges of the inside
main body 7a, in a total of three portions constituted of the
circumferential direction central portion of the inner peripheral
edge and the two portions of the outer peripheral edge existing
near to the circumferential direction two ends thereof, there are
formed the inside locking pieces 8d, 8e and 8f which are
respectively folded toward the pressure plate 2a. The respective
front half sections of the inside locking pieces 8d, 8e and 8f are
folded to a state where the angles relative to the inside main body
7a provide acute angles, and they can be mounted onto the back
surface side of the pressure plate 2a the front half parts while
being elastically deformed in a direction to increase their mutual
distance in the radial direction.
When mounting the above-structured inside shim plate 3a onto the
pressure plate 2a, the inside main body 7a is contacted with the
back surface of the pressure plate 2a while the front half section
inner surface of the inside locking piece 8d is elastically
contacted with the inside locking recess 18 of the inner peripheral
edge of the pressure plate 2a and the front half section inner
surfaces of the two inside locking pieces 8e, 8f are elastically
contacted with such two positions of the pressure plate 2a as exist
near to the circumferential direction two ends of the outer
peripheral edge of the pressure plate 2a. And, in the thus-mounted
state, the shifting movement of the inside shim plate 3a in the
radial and circumferential directions is limited by a friction
force acting between the inside shim 3a and the back surface of the
pressure plate 2a, engagement (on a non-linear line) between the
two inside locking pieces 8e, 8f and the outer peripheral edge of
the pressure plate 2a, and the like.
Meanwhile, the outside shim plate 4a is formed by punching and
bending a corrosion resistant and elastic metal plate such as a
stainless spring steel plate by press working, and includes a flat
plate-shaped outside main body 12a and three outside locking pieces
13d, 13e and 13f.
In this embodiment, of the outside main body 12a, in the
circumferential direction two parts existing across a part to be
contacted with the leading end face of the piston 14a, there are
formed engaging holes 26, 26 for insertion of the engaging
projections 19, 19. As shown in FIG. 2, the two engaging
projections 19, 19 are respectively formed in an oval shape (long
in the circumferential direction) in which the circumferential
direction dimension is larger than the radial-direction dimension,
while the inner peripheral edge of each engaging hole 26 is formed
such that a pair of linear parts 27a, 27b respectively arranged in
the two radial-direction parts and a pair of concave arc parts 28,
28 respectively arranged in the circumferential direction two parts
continue with each other. Also, in this embodiment, the two linear
parts 27a, 27b are slightly inclined in a direction to approach
each other along the radial direction as they go toward the center
side (the side of the axis O of the piston 14a) along the
circumferential direction. And, in a state where the leading ends
of the engaging projections 19, 19 are inserted in the
thus-structured engaging holes 26, 26, the plane parts 20a, 20b and
the linear parts 27a, 27b are opposed to each other in the radial
direction, and the convex arc surface parts 21, 21 and the concave
arc parts 28, 28 are opposed to each other in the circumferential
direction.
Also, the radial-direction width dimension H.sub.26 of the engaging
holes 26, 26 (the minimum value of the radial-direction width
dimension in the part opposed to the engaging projection 19) is set
slightly larger than the radial-direction width dimension H.sub.19
of the engaging projections 19, 19 (as small as possible so long as
the engaging projection can be inserted), whereas the
circumferential direction width dimension L.sub.26 of the engaging
holes 26, 26 is set sufficiently larger than the circumferential
direction width dimension L.sub.19 of the engaging projections 19,
19. Thus, as shown in FIG. 1, in a state where the outside shim
plate 4a exists at a neutral position with respect to the pressure
plate 2a, between the plane parts 20a, 20b and the linear parts
27a, 27b, there are respectively formed small clearances in which
the width dimension along the radial direction varies gradually
along the circumferential direction; and, between the convex arc
surface parts 21, 21 and the concave arc parts 28, 28 opposed to
each other in the circumferential direction, there are respectively
formed circumferential direction clearances (L1, L2) in which the
width dimension along the circumferential direction is relatively
large). Also, in this embodiment, in a state where the outside shim
plate 4a exists at a neutral position with respect to the pressure
plate 2a, the inclination angle between the plane parts 20a, 20b
and the linear parts 27a, 27b opposed to each other in the radial
direction through the small clearances is restricted to the range
of 0.degree..about.15.degree. (in the illustrated example,
1.5.degree.).
Also, the outside main body 12a includes, in the radial-direction
middle portions of the circumferential direction two end edges
thereof, locking projection pieces 29, 29 respectively projecting
more in the circumferential direction than the radial-direction
adjoining portions. And, the distance L.sub.29 between the leading
end edges of the two locking projection pieces 29, 29 is set larger
than the clearance D.sub.22 between the two locking folded parts
22, 22 formed in the circumferential direction two ends of the
inside shim plate 3a (L.sub.29>D.sub.22). However, the
dimensions L.sub.29, D.sub.22 are regulated in the following manner
with respect to the guide inclination parts 25, 25. That is, the
dimensions of the respective parts are regulated in such a manner
that, in the circumferential direction one end edge of the outside
main body 12a, in a state where, while the locking projection piece
29 is engaged with the locking open hole 24, the outside main body
12a approaches the inside main body 7a of the shim plate 3a, the
leading end edge of the locking projection piece 29 on the
circumferential direction other end side is contacted with the
guide inclination part 25 formed in the leading end of the locking
bent part 22. Also, the circumferential direction length L.sub.12
of such part of the outside main body 12a as exists between the two
locking folded parts 22, 22 and also adjoins the radial-direction
two sides of the two locking projection pieces 29, 29 is set
slightly smaller than the clearance D.sub.22
(L.sub.12<D.sub.22).
Further, of the inner and outer two peripheral edges of the outside
main body 12a, in a total of three portions including the
circumferential direction central portion of the outer peripheral
edge and the two such portions of the inner peripheral edge as
exist near to the circumferential direction two ends, there are
provided the outside locking pieces 13d, 13e and 13f respectively
folded toward the pressure plate 2a. In such outside locking pieces
13d, 13e and 13f as well, similarly to the above-mentioned inside
locking pieces 8d, 8e and 8f, the front half sections thereof are
folded until the angles thereof with respect to the outside main
body 12a provide acute angles, whereby they can be mounted onto the
back surface side of the pressure plate 2a through the inside shim
plate 3a.
In this embodiment, to enable the circumferential direction slight
shifting movement of the outside shim plate 4a with respect to the
pressure plate 2a, the circumferential direction width W.sub.10 of
the locking recess 10a is set slightly larger than the
circumferential direction width W.sub.13 of the outside locking
piece 13d (W.sub.10>W.sub.13). Also, the clearance D.sub.11
between the two steps 11a, 11 a is set slightly larger than the
distance L.sub.13 between the circumferential direction outside
edges (opposite side end edges) of the two outside locking pieces
13e and 13f (D.sub.11>L.sub.13).
Also, the circumferential direction shifting movement of the
outside shim plate 4a with respect to the pressure plate 2a is
regulated by the engaged portion between the circumferential
direction side edge of the outside locking piece 13d and the
locking recess 10a, or, by the engaged portions between the
circumferential direction outside edges of the outside locking
pieces 13e, 13f and the steps 11a, 11a, but is not regulated by the
engagement between the engaging holes 26, 26 and the engaging
projections 19, 19. Therefore, the dimensions of the respective
parts are regulated in the following manner. That is, as shown in
FIG. 1, in the outside shim plate 4a, in a state where it exists at
a neutral position relative to the pressure plate 2a,
circumferential direction clearances L1, L2 between the
circumferential direction end edges (the top portions of the convex
arc surface parts 21) of the engaging projections 19, 19 and the
circumferential direction end edges (the bottom portions of the
concave arc parts 28) of the two engaging holes 26, 26 are
respectively set larger than the size La ((W.sub.10-W.sub.13)/2) of
the circumferential direction clearance between the circumferential
direction side edge of the outside locking piece 13d and the
locking recess 10a and the size Lb ((D.sub.11-L.sub.13)/2) of the
circumferential direction clearance between the circumferential
direction outside edges of the outside locking pieces 13e, 13f and
the steps 11a, 11a (L1, L2>La, Lb). Thus, in this embodiment,
even when the outside shim plate 4a is shifted in the
circumferential direction with respect to the pressure plate 2a,
the engaging projections 19, 19 and the engaging holes 26, 26 are
prevented against contact with each other.
The above-structured outside shim plate 4a is mounted onto the
pressure plate 2a in a state where the outside main body 12a
thereof is superimposed on the back surface of the pressure plate
2a through the inside main body 7a thereof. And, in this state, the
inside shim plate 3a and the outside shim plate 4a are combined
with each other in such a manner that they can shift slightly
relative to each other in the peripheral and radial directions.
In a state where the two shim plates 3a and 4a are assembled to the
pressure plate 2a, the inside shim plate 3a is regulated
(substantially prevented) against shifting movement with respect to
the pressure plate 2a in the peripheral and radial directions,
whereas the outside shim plate 4a is allowed to shift slightly with
respect to the pressure plate 2a in the peripheral and radial
directions and around the axis O of the piston 14a.
Here, the two shim plates 3a and 4a may also be assembled to the
pressure plate 2a after they are previously assembled together, or
the inside and outside shim plates 3a and 4a may also be
sequentially assembled to the pressure plate 2a.
Also, in this embodiment, on the back surface of the pressure plate
2a, there is mounted a wear indicator 55 formed by bending a long
plate-shaped metal thin plate such as a spring steel plate into a
substantially U-like shape. Thus, from wear occurring in braking,
it is possible to detect that the lining 6 has been worn up to the
wear allowance limit thickness.
The above-structured disc brake pad assembly 15 of this embodiment,
as shown in FIG. 6, is arranged opposed to the inner side surface
of the rotor 17 and is incorporated into the disc brake 16 equipped
with an electric parking mechanism. Here, in this embodiment, the
disc brake pad assembly 15 of this embodiment is arranged also in a
portion opposed to the outer side surface of the rotor 17, thereby
enabling common use of parts and thus cost reduction. However, on
the outer side of the rotor 17, there can also be used a disc brake
pad assembly of a conventional structure excluding the engaging
projection 19, through hole 23 and engaging hole 26.
The illustrated disc brake 16 with an electric parking mechanism is
a floating type disc brake structured such that a caliper 31
incorporating a piston 14a on the inner side is axially shiftably
supported by a support 30 on which a pair of disc brake pad
assemblies 15, 15 are axially shiftably supported. Also, the
support 30 is fixed to a vehicle body in a state where it exists
adjacent to the rotor 17 rotatable together with a wheel.
The caliper 31 includes a caliper pawl part 32 in the outer side
end and a cylinder part 33 in the inner side end. And, within the
cylinder part 33, there is mounted the piston 14a oil tight and
axially shiftably. Also, inside the cylinder part 33, there is
provided a conversion mechanism (feed screw mechanism) 34 for
converting the rotation motion of the output shaft of an electric
motor (to be discussed later) to linear motion. The conversion
mechanism 34 includes a spindle 36 having a male screw part 35 in
the outer peripheral surface thereof and a nut 38 having a female
screw part 37 in the inner peripheral surface and screwed to the
spindle 36. And, a male spline part 39 formed in the outer
peripheral surface of the nut 38 is engaged relatively unrotatably
and axially shiftably with a male spline part 41 formed in the
inner peripheral surface of a cylindrical part 40 constituting the
piston 14a. Also, the spindle 36 includes a flange part 42 in the
axial-direction middle part thereof and, between the inner side
surface of the flange part 42 and the inner surface (outer side
surface) of a bottom part 43 constituting the cylinder part 33,
there is provided a thrust needle bearing 44. Also, the inner side
end of the spindle 36 is inserted into a communication hole 45
formed to penetrate axially through the central portion of the
bottom part 43.
Also, within a casing 46 fixedly supported to the inner side end of
the caliper 31, there are stored an electric motor and a reduction
gear (neither of which is shown). And, the leading end of an
intermediate shaft 48 with a final gear constituting the reduction
gear fixed to the periphery thereof is spline engaged into a female
spline hole 47 opened in the central portion of the inner side end
(base end) of the spindle 36.
Also, in the near-to-outside portion of the inner peripheral
surface of the cylinder part 33, there is formed a seal groove 49
having a rectangular-shaped section, and an annular seal member 50
mounted in the seal groove 49 seals between the outer peripheral
surface of the piston 14a and the near-to-outside portion of the
inner peripheral surface of the cylinder part 33. Also, a space
between the opening of the cylinder part 33 and the leading end
outer peripheral surface of the piston 14a is closed by a dust
cover 51.
Particularly, in this embodiment, between the leading end face of
the piston 14a and the inner side disc brake pad assembly 15, there
is not employed a rotation preventive structure using a dowel and a
recess such as the above-mentioned conventional structure. That is,
the leading end face of the piston 14a is simply in contact with
the back surface of the outside main body 12a of the outside shim
plate 4a constituting the inner side disc brake pad assembly 15. In
this embodiment, the piston 14a is prevented against rotation by
the friction force acting between the outside shim plate 4a and
piston 14a and the friction force given by the annular seal member
50. Thus, in this embodiment, for the piston 14a, a rotation
preventive structure based on mechanical engagement is not
employed. Thus, in the braking time and braking removal time of the
parking brake, the piston 14a rotates slightly relative to the
cylinder part 33. Here, in this embodiment, since the braking of a
service brake is executed by feeding pressure oil into the cylinder
part 33, the piston 14a is prevented against rotation.
Also, in this embodiment, for enhancement in the operation
efficiency of the assembling operation of the above-structured disc
brake 16 with an electric parking mechanism, the flange part 42
constituting the spindle 36 and the above-mentioned piston 14a are
improved. Specifically, in the continuous part between the side
surface and outer peripheral surface of the flange part 42, there
is formed a convex curved surface part 52 the section of which has
a convex arc shape; and, in the inner side end inner peripheral
edge of a cylindrical part 40 constituting the piston 14a, there is
formed a linear shaped or curved-surface shaped (concave arc
shaped) chamfer part 53. And, in the assembling operation of the
disc brake 16 with an electric parking mechanism, when the
conversion mechanism 34 constituted of a combination of the spindle
36 and the nut 38 is assembled inside the piston 14a with the
leading end face of which is placed on an operation table, the
convex curved surface part 52 of the flange part 42 is contacted
with the chamfer part 53, whereby, using the deadweight of the
conversion mechanism 34, the center of the conversion mechanism 34
is allowed to coincide with the center of the piston 14a.
To operate a parking brake by the disc brake 16 with an electric
parking mechanism according to this embodiment, a driver may
operate a lever or a switch to supply a control current to the
electric motor, thereby rotating the output shaft of the electric
motor. Such rotation motion is transmitted to the spindle 36 while
it is reduced at a specific reduction ratio through the reduction
gear. The rotation motion transmitted to the spindle 36, due to
threaded engagement between the male screw part 35 of the spindle
36 and the female part 37 of the nut 38, is converted to linear
motion to shift the nut 38 toward the rotor 17. Further, the linear
motion of the nut 38 shifts the piston 14a toward the rotor 17 (to
the left in FIG. 6), thereby pressing the inner side disc brake pad
assembly 15 (the lining 6 constituting the pad 1a) against the
inner side surface of the rotor 17. Accordingly, as the reaction of
this pressing force, the caliper pawl part 32 of the caliper 31
presses the outer side disc brake pad assembly 15 (the lining 6
constituting the pad 1a) against the outer side surface of the
rotor 17. On the other hand, to remove the operation of the parking
brake, by rotating reversely the electric motor, the piston 14a is
shifted in a direction to part apart from the rotor 17, whereby the
two disc brake pad assemblies 15, 15 are separated from the rotor
17.
According to the above-structured disc brake pad assembly 15 of
this embodiment, even when it is used while incorporated into the
disc brake 16 with an electric parking mechanism, the outside
locking pieces 13d, 13e, 13f constituting the outside shim plate 4a
can be effectively prevented against plastic deformation or
damage.
That is, in this embodiment, in a state where the engaging
projections 19, 19 formed in the pressure plate 2a are inserted
into the engaging holes 26, 26 formed in the outside shim plate 4a,
a pair of flat surface parts 20a, 20b constituting the side
surfaces of the engaging projections 19, 19 and a pair of linear
parts 27a, 27b constituting the inner peripheral edges of the
engaging holes 26, 26 are opposed to each other; and, in a state
where the outside shim plate 4a exists at a neutral position with
respect to the pressure plate 2a, the flat surface parts 20a, 20b
and the linear parts 27a, 27b are inclined to each other. And,
while the parking brake is in braking, the counterclockwise
rotation of the outside shim plate 4a about the axis O based on a
rotation force applied from the leading end face of the piston 14a
is regulated, as shown in FIG. 7, because simultaneously when the
linear part 27b constituting the engaging hole 26 on the
circumferential direction one end side (in FIG. 7, the right end
side) and the flat surface part 20b constituting the side surface
of the engaging projection 19 inserted into this engaging hole 26
are line contacted with each other, the linear part 27a
constituting the engaging hole 26 on the circumferential direction
other end side (in FIG. 7, the left end side) and the flat surface
part 20a constituting the side surface of the engaging projection
19 inserted into this engaging hole 26 are line contacted with each
other. Also, in the braking removal time of the parking brake, the
clockwise rotation of the outside shim plate 4a about the axis O is
regulated, as shown in FIG. 8, because, simultaneously when the
linear part 27a constituting the engaging hole 26 on the
circumferential direction one end side and the flat surface part
20a constituting the side surface of the engaging projection 19
inserted into this engaging hole 26 are line contacted with each
other, the linear part 27b constituting the circumferential
direction other end side and the flat surface part 20b constituting
the side surface of the engaging projection 19 inserted into this
engaging hole 26 are line contacted with each other.
As described above, in this embodiment, in any case of the braking
time and braking removal time of the parking brake, the rotation
force applied from the leading end face of the piston 14a to the
outside shim plate 4a may not be supported by the engaged parts
between the outside locking pieces 13d, 13e, 13f formed in the
peripheral edge of this outside shim plate 4a and the peripheral
edge of the pressure plate 2a, or, when supported, the supporting
force can be reduced. Therefore, according to the structure of this
embodiment, the outside locking pieces 13d, 13e, 13f can be
effectively prevented against plastic deformation or damage such as
breakage.
Further, in this embodiment, since the rotation force applied from
the leading end face of the piston 14a to the outside shim plate 4a
is supported not by a portion to be point contacted but by a
portion to be line contacted between the flat surface parts 20a,
20b and the linear parts 27a, 27b, stress acting on the engaging
projections 19, 19 can be suppressed. Moreover, in this embodiment,
the rotation force is supported by the two contact portions
existing on both sides in the circumferential direction, thereby
enabling reduction by half of the stress acting on the engaging
projections 19, 19. Thus, the disc brake pad assembly of this
embodiment can effectively prevent the side surfaces of the
engaging projections 19, 19 and the inner peripheral edges of the
engaging holes 26, 26 against serious wear or deformation.
Second Embodiment
FIG. 9 shows a second embodiment of the invention. In this
embodiment, the inner peripheral edge of an engaging hole 26a
formed in an outside shim plate 4b is structured in such a manner
that a pair of mutually parallel linear parts 27c, 27d arranged in
two side parts in the radial direction and a pair of concave arc
parts 28, 28 arranged in two side parts in the circumferential
direction are formed to continue with each other. Also, the side
surface of an engaging projection 19a formed on the back surface of
a pressure plate 2b is structured in such a manner that a pair of
flat surface parts 20c, 20d arranged in two side parts in the
radial direction and a pair of convex arc surface parts 21, 21
arranged in two side parts in the circumferential direction are
formed to continue with each other. And, the two flat surface parts
20c, 20d are inclined along the radial direction in a direction to
approach each other as they go along the circumferential direction
toward the opposite side (in FIG. 9, the right side) of the axis O
of the piston 14a.
Also, in a state where the outside shim plate 4b exists at a
neutral position with respect to the pressure plate 2b, between the
flat surface parts 20c, 20d and two linear parts 27c, 27d opposed
to each other in the radial direction, there are formed small
clearances the with dimensions along the radial direction of which
respectively change gradually along the circumferential direction;
and, between the convex arc surface parts 21, 21 and the concave
arc parts 28, 28 opposed to each other in the circumferential
direction, there are formed clearances the width dimensions along
the circumferential direction of which are relatively large. And,
the inclination angle between the flat surface parts 20c, 20d and
the two linear parts 27c, 27d opposed to each other in the radial
direction through the small clearances is regulated in the range of
0.degree..about.15.degree. (in the illustrated example,
1.5.degree.).
In this embodiment having the above structure as well, in the
braking time and braking removal time of the parking brake, the
flat surface parts 20c, 20d and the two linear parts 27c, 27d can
be line contacted with each other. Therefore, the disc brake pad
assembly of this embodiment can effectively prevent the outside
locking pieces 13d, 13e, 13f (see FIG. 1 and so on) constituting
the outside shim plate 4b against plastic deformation and damage
such as breakage.
The remaining structures and operation effects are similar to the
above-mentioned first embodiment.
Third Embodiment
FIGS. 10 and 11 show a third embodiment of the invention. In this
embodiment, in an outside main body 12a constituting an outside
shim plate 4c, there is formed an engaging hole 26b having a
substantially H-like shape. Also, of the inner peripheral edge of
the engaging hole 26b, the radial-direction two side portions of
the circumferential direction central part (the part the
radial-direction width dimension of which is smaller than the
circumferential direction two side portions) are respectively
folded on the opposite side (in FIG. 11, on the left side) to the
pressure plate 2a, thereby forming folded parts 54, 54 therein
respectively. And, in this embodiment, the mutually opposed inside
surfaces of the two folded parts 54, 54 function as linear parts
27e, 27f respectively. That is, in the braking time and braking
removal time of the parking brake, flat surface parts 20a, 20b
constituting the side surfaces of an engaging projection 19 and the
linear parts 27e, 27f serving as the inside surfaces of the folded
parts 54, 54 are line contacted with each other. Also, the linear
parts 27e, 27f are inclined along the radial direction in a
direction to approach each other as they go toward the inside (in
FIG. 10, the left side) along the circumferential direction.
In this embodiment having the above structure, since the contact
area between the flat surface parts 20a, 20b and the linear parts
27e, 27f can be secured large, contact surface pressures acting on
these parts can be reduced. Thus, the disc brake pad assembly of
this embodiment can prevent more effectively the side surfaces of
the engaging projections 19 and the inner peripheral edges of the
engaging holes 26b against serious wear or deformation.
The remaining structures and operation effects are similar to the
above-mentioned first embodiment.
Here, the characteristics of the above-mentioned embodiments of the
disc brake pad assembly of the invention are collectively described
in brief.
[1] A disc brake pad assembly (15), comprising: a pad (1a)
including a pressure plate (2a) with a lining (6) fixedly attached
to the front surface thereof, and arranged opposed to the
axial-direction side surface of a rotor (17); and, a shim plate
(inside shim plate 3a, outside shim plate 4a) having a back surface
to be pressed by the leading end face of a piston (14a), the shim
plate (outside shim plate 4a) including a flat plate-shaped main
body (outside main body 12a) and locking pieces (outside locking
pieces 13d, 13e, 13f) folded from the peripheral edge of the main
body (outside main body 12a) toward the pressure plate (2a) and,
the locking pieces (outside locking pieces 13d, 13e, 13f) being
engaged with the peripheral edge of the pressure plate (2a) in a
state where the front surface of the main body (outside main body
12a) is superimposed directly or through the other shim plate
(inside shim plate 3a) on the back surface of the pressure plate
(2a), wherein the back surface of the pressure plate (2a) includes,
in the part thereof shifted from the part thereof opposed to the
leading end face of the piston (14a), an engaging projection (19)
projecting in the axial direction of the rotor (17); the engaging
projection (19) is inserted into an engaging hole (26) formed in
such part of the main body (outside main body 12a) of the shim
plate (outside shim plate 4a) as is shifted from the part thereof
to be contacted with the leading end face of the piston (14a) in a
state where flat surface parts (20a, 20b) constituting the side
surface of the engaging projection (19) and linear parts (27a, 27b)
constituting the inner peripheral edge of the engaging hole (26)
are opposed to each other, and, with the shim plate (outside shim
plate 4a) existing at a neutral position with respect to the
pressure plate (2a), the flat surface parts (20a, 20b) and the
linear parts (27a, 27b) are inclined to each other; of the shifting
movement of the shim plate (outside shim plate 4a), the movement
thereof in the circumferential direction of the rotor (17) is
regulated by the engaged portions between the locking pieces
(outside main body 12a) and the peripheral edge of the pressure
plate (2a); and, of the rotation of the shim plate about the axis
(O) of the piston (14a), the rotation in a direction to act on the
piston (14a) at least in braking is regulated by line contact
between the flat surface parts (20a, 20b) and the linear parts
(27a, 27b). [2] A disc brake pad assembly (15) according to the
above [1] item, wherein, in a state where the shim plate (outside
shim plate 4a) exists at a neutral position with respect to the
pressure plate (2a), the inclination angle between the flat surface
parts (20a, 20b) and the linear parts (27a, 27b) is in the range of
0.degree. .about.15.degree.. [3] A disc brake pad assembly (15)
according to any one of the above [1] and [2] items, further
including a folded part folded from the inner peripheral edge of
the engaging hole (26) toward the opposite side to the pressure
plate (2a), wherein the inside surface of the folded part is
constituted of the linear parts (27a, 27b). [4] A disc brake pad
assembly (15) according to any one of the above [1] .about.[3]
items, wherein the engaging projection (19) is formed in such
circumferential direction two side parts of the back surface of the
pressure plate (2a) as are disposed across the part thereof opposed
to the leading end face of the piston (14a), and the engaging hole
(26) is formed in such circumferential direction two side parts of
the main body (outside main body 12a) of the shim plate (outside
shim plate 4a) as are disposed across the part thereof to be
contacted with the leading end face of the piston (14a). [5] A disc
brake pad assembly (15) according to any one of the above
[1].about.[4] items, wherein a pair of flat surface parts (20a,
20b) are formed in the side surface of the engaging projection
(19), a pair of linear parts (27a, 27b) are formed in the inner
peripheral edge of the engaging hole (26), and the rotation of the
shim plate in both directions about the axis (O) of the piston
(14a) is regulated by line contact between the flat surface parts
(20a, 20b) and the linear parts (27a, 27b). [6] A disc brake pad
assembly (15) according to any one of the above [1].about.[5]
items, wherein the locking pieces (outside locking pieces 13d, 13e,
130 are formed in the outer and inner peripheral edges of the main
body (12a) at least apiece.
Here, the disc brake pad assembly of the invention is not limited
to the above embodiments but can be modified or improved properly.
Also, the materials, shapes, dimensions, number, arranging
locations and the like of the respective composing elements of the
above embodiments are not limitative but are arbitrary so long as
they can attain the invention.
Also, the present application is based on the JPA (patent
application No. 2014-118648) filed on Jun. 9, 2014 and thus the
contents thereof hare incorporated herein for reference.
INDUSTRIAL APPLICABILITY
The number of shim plates constituting the disc brake pad assembly
of the invention is not limited to 2. The invention can be enforced
using only a single shim plate (excluding the inside shim plate
from the structure of the embodiments), or, reversely, the
invention can also be enforced using a structure in which the third
shim plate (for example, the intermediate shim plate) is sandwiched
between the pressure plate and inside shim plate or between the
inside and outside shim plates. Also, the disc brake pad assembly
of the invention is not limited to a floating type disc brake with
an electric parking mechanism but can also be used while it is
incorporated into electric disc brakes of various structures.
Further, the number, forming positions and forming directions of
the engaging projections and engaging holes are not limited to the
illustrated embodiments but, so long as the effects of the
invention can be provided, the structures of the embodiments can be
properly combined with each other or can be changed properly.
DESCRIPTION OF REFERENCE NUMERALS AND SIGNS
1, 1a: Pad 2, 2a, 2b: Pressure plate 3, 3a: Inside shim plate (shim
plate) 4, 4a, 4b: Outside shim plate (shim plate) 5: Combined shim
plate 6: Lining 7, 7a: Inside main body 8a.about.8f: Inside locking
pieces 9: Open hole 10, 10a: Locking concave part 11, 11a: Step 12,
12a: Outside main body (main body) 13a.about.13f: Outside locking
pieces 14: Piston 15: Disc brake pad assembly 16: Disc brake with
an electric parking mechanism 17: Rotor 18: Inside diameter side
locking concave part 19, 19a: Engaging projection 20a.about.20d:
Flat surface parts 21: Convex arc surface part 22: Locking folded
part 23: Through hole 24: Locking open hole 25: Guide inclination
part 26, 26a, 26b: Engaging hole 27a.about.27f: Linear part 28:
Concave arc part 29: Locking projection piece 30: Support 31:
Caliper 32: Caliper pawl part 33: Cylinder part 34: Conversion
mechanism 35: Male screw part 36: Spindle 37: Female screw part 38:
Nut 39: Male spline part 40: Cylindrical part 41: Female spline
part 42: Flange part 43: Bottom part 44: Thrust needle bearing 45:
Communication hole 46: Casing 47: Female spline hole 48:
Intermediate shaft 49: Seal groove 50: Annular seal member 51: Dust
cover 52: Convex curved surface part 53: Chamfer part 54: Folded
part 55: Wear indicator
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